Pneumatic-tire pressure-gage



'K1 E. LEES. PNEUMATC- URE PRESSURE GAGE. APPLICATION r|LEDvv1AN.2a.1919.

Patented Jan. 20, 1920.

lllllll-Illlllllll Il i UNITED sTATEs PATENT oEEioE.-

KENNETH F. LEES, 0F NEW HAVEN, CONNECTICUT. l

APNET.T1V.| A'J.IC-TIRE PRESSURE-GAGE.

V'.appliea'ion inea January as, 19,19. serial No. 273,615.

To all whom it may concern: y

Be it known that I, KENNETH F. LEES, a citizen of the United States, residing at New Haven, in the county of New Haven and State of Connecticut, have invented or discovered certain new and useful Improvement-s in Pneumatic-Tire Pressure-Gages, of which the, following is a specification, reference being had therein to theaccompanying drawing. i

This invention relates to that class of tire test pressure gages intended to be permanently attached to'the air inlet tubes of pneumatic tires, and the invention has for its object to provide a pressure gage of this class which is of comparatively simple construction, andnvhich is specially made so as to indicate safety 'minimum and maximum air pressures for any particular tire to which it may be appliedn In the accompanying drawing Figure 1 is an elevation 0f the improved pressure gage.- Fig. 2 is a vertical section of the same showing the parts in normal position, and Fig. 3 is'a similar section illustrating the operation of the device attached to a tire valve stem. Fig. hitis a detail section on line i-f4, Fig. 2, and Fig. 5 a detailof a pre ferred arrangement of pressure-indicating figures or characters.

Referring to the drawing, 12 denotes the v main casing part and 13 a supplemental casing part or cyhnder having a screw-threaded connection with the casing part 1 2. Formed integral with the casing part 12 1s an internally screw-threaded bottom part 121 which is adapted to fit the screw-threaded nipple. part of a pneumatic tire valve stem 16, so as to attach the pressure gage .to said stem, said part 12a having an attached packing washer 15 to make an air-tight joint between said bottom .part 12a and said valve stem. Fitting tightly within the casing part.

or cylinder 12 is a plunger or piston 17 comprising a usual cup leather. vSurrounding the shank 18v of the said piston is a strong spring 19 interposed between thejsaid piston and a cap 2O which isipreferably permanently attached to the outer end of. the casing part 12 and constitutes a cylinder head.

The piston shank 18 is. bored out or formed hollow for the passage of a' tire valve relief pin 23 which is arranged to register with the stem 24 of the tire valve, so`

that when theA air pressure of a tire is to be testedl the said pin 23 may be depressed to Specification of Letters Patent.

Patented Jan. 20, 1920.

open the tire valve so as'to admit compressed air into the chamber 25`of the casing part 12 and thus lift orforce outward the piston 17. The piston shank 18 is. counterbored at its top for the reception of a light spring 26 which is interposed between a collar 27 on the relief pin 23 and a shoulder part on the said piston shank, saidv spring servin to hold up the relief pin but permitting 1t to be depressed when the tire pressure is to be tested. The said spring 26 also serves vas a pressureresisting spring in holding down the piston 17, so that the stress of both springs 19 and 26 must be overcome by the tire air pressure when said piston is lifted. Thev outer or upper portion 'of the shank 1 8 is cut away to form two extensions 18a which project upward through holes in the cap 20 and are riveted at their tops to an. index plate 28 which is thus lifted withv the piston 17 when the tire pressure is to be tested. The upper enlarged portion 23a of the relief pin 23 may be provided with pressure-indicating figures which will be read in connection with the indeX plate 28 when the latter is lifted, and the said relief pin is. preferably provided `with a head or button 29 by which it may be conveniently depressed against-the stress of the spring 26. Instead ofproviding the enlarged part 23a with pressure-indicating figures such figures may be placed on one or both of the eXtens-ions 18a of the piston shank 18, as indicated in Fig. 5, and this will be' the preferable location of such figures. When the pressure- .indicating figures are placed upon 'the extensions'lSa of the piston shank 18 the top of the cap 20 will serve as the index in reading the pressure-indicating figures as the said extensions are lifted above the top of said cap.

' A packing washer 30 is preferably interposed between the collar 27 and the inner wall of the cap 20 -to make a tight jointaround the relief pin at this point. A simiros In the use of the invention 'the pressure" gage is attached to the valve stem 16 of a pneumatic tire, as shown in Fig. 3.

"practice the auxiliary casing 1 3 will fit againsta shoulder of af nut, as 34, on the rim 35 of the wheel, and when screwed down "-tightly against said shoulder will serve as' la lock nut to hold'the pressure When the pressure ga age in lace. ge is to ge appliredto a1 valve vstem which pro]ec,ts to a considerable "distance beyond the rim of the -wheel a. 'second supplemental casing 14;, as shown in the drawings, 'will be 4employed,`and this supplemental .casing i4 will serve'fas a lock nut when screwed `tightly against the shoulder of a nut' 34, as indicated in Fig. 3.

When tl'iepressure is to be tested the ren lief pin 23 isjfdepressed, as denoted by dotted relief. pin appearing above the top ofl they?,

cap 20. Or if the extensions 18a beprovi'dejdfwith pressure-indicating figures or charac` ters, which is preferred, the pressure will be denoted by the positions of such figures or characters relative to the top of the cap 20 wliich'will serve as an indexe or pointeiz When the piston islifted thel relief pin remains stationary," as, the pistoiifis movable independently of said pin, as lwill'be under-K stood, the latterbeing normallystationary.

yThe springs 19 and 26" are of sufficient A sttength so that their combined stressl will red mark, as at 18b in Fig. 5.

not be overcome by anl unsafe minimum pressure'within the tire to which the-pressure gage is applied. To thisend, the relative positions, or spacing, of the piston 1'( and index plate or stop member 28 are such that the spring 19 is held'under a pr e fj determined initial compression between said while the pressure responsive member is piston and the cylinder head 2O whensaid stop member is in engagement.' with saidcyl inder head, as shown in Fig. 2. From this it results that if, on depressingthe valve relief pin 23,'the gage fails to show any pres-- sure at all, it will be understood that the pressi re in the tire is unsafe or is below a safety running point. To indicate what may be termed a maximum safety pressure for any tire to which the pressure gage may be attached the partcarrying the pressureindicatingl figures may be provided with a This maximum safety-indicating mark would'be differen'tly located for different sized tires, or for tires adapted to different air pressures, and in this way any safety pressure for any sized tire to which the gage is to be applied would be properly calibrated. ,Ofcoursefor different vsized tires intended to `earryis seated the piston in the pressure gage will weights to be carried oy the tires, as other- 'pulsioin and waste of gasolene or other result.. It is therefore important that pneumatic tires should be frequently tested to claim dand desire to secure-bylwLetters Patv different air pressures' the stress of the springs 19 and26 would alsov be properlT` varied so1 that yasafety minimum pressure for any particular tire to which the gagr may be applied would thus be' properly calibrated.

As hereinbefore indicated, the improved pressure gage is intended to be permanently attached to the tire valve stem of a pneumatic tire and when the valve in said stem be normally inactive' and the index plate 28 will bein contact with the cap 20 and no tire pressure 'will be indicated. It is important, to prevent undue wear and strain onv a pneumatic" tire that the 'air pressure therein should not fall below what is hereinbefore` termed an unsafev mininumpressure, which of course will vary with different sizes and makesorf tires and different wisethe running of too soft a tire will result in undue we ar thereon, and with too soft tires a car will require more power for prohydrocarbon used as fuel will accordingly determine whether or not Vthe air pressure therein. has fallen belowan unsafe minimum, aiidin using Athis improved pressure gage this-can be done quickly by depressing the relief pinl 23; and if on so doing thel -tire air pressure is insufficient to overcome the stress of' the properly graduated spring pressure against the piston the index plate 28 will not be lifted and it will thus in-. stantly appear that the-tire air pressure is below anunsafe minimum. VIt will therefore be apparent that a pressure Oage provided with means for quickly and colriveniently del termining an-unsafe minimum air pressure e 1in "a pneumatic tire is an important and .Valuable device, and that the presentv in- Vention supplies such a device. 1 f

` It, will, of course', be understood that, 110

amount, but adapted to yield under pressures exceeding such amount, may be employed if preferred. v

Having thus described my invention I ent: i,

1. In a tire pressure gage, e combination with a casing providedl with!` means Nfor attachment to. a'tire and with means where-A by communication ji'nayg "be vvestablished' between the interior ofy said casing and the in- 125 terioi 'of said tirefof a movable member" ivithin said casingfand subjected to the pressure in the tire when Vsuch communication is established, means coperatingwith said` vi'fiember for preventing pressure indicating 130 l moven'ient thereof under pressures below a predetermined amount and for pern'iitting such movement thereof when said amount is exceeded. and means operated by said member for indicating i'novement thereof.

Q. ln a tire pr gage, the combination with a casing and utn'mally inoperative means for at will establishing communication between the interior of said casing and the interior of the tire. of a movable member within said casing subjected to the pies sure in the tire when said communication is established, means coi'perating with said member for preventingV pre ure indicating movement thereof under pressures below a predetermined amount and for permitting such movement thereof when said amount is exceeded, and means operated by said member l'or indicatingr movement thereof.

In a tire pressure. gage, the combina- 'tion with a asing provided with means for attachment to a tire valve stem. of a plunger in said casing. a manually operated pin extending axially through said plunge' for operating the tire valve to admit the pressure in the tire to said plunger, means cooperating with said plunger Yl'or preventing pressure indicating moi einem thereof under pressures below a predetermined amount and for permitting such movement. thereof when said` amount is exceeded, and means operated 'by said plunger for indicating movement thereof. Y

4. In a tire pressure gage. the combination with a casing provided with means for attachment to a tire and with means whereby communication may be established hetween the interior of said casing and the in* terior of said tire, of a movable member' within said casing and subjected to the pressure in the tire when such communication is established. means cope ating with said member for preventing pressure indicating movement thereof under pressures below a predetermined amount and for permitting' such movement thereof when said amount is exceeded, and means operated by said member for indicating movement thereof and for measuring the amount of such movement.

In al tire pressure gage, the combina` tion with a casing provided with means for attachment to a. tire and with means whereby communication may be established between the interior of said casing and the interior of said tire. of a. movable member within said casing and subjected to the pressure in the tire when such communication is established, means including ya spring under a predetermined initial tension for preventing movement of said member under pressures below a predetermined amount and for permitting such movement thereof when said amount is exceeded, and means operated by said member for indicating movement thereof.

G. In a tire pressure gage, the eon'ibination with a cylinder.provided at its outer end with a head and at its inner end with means for attachment to a tire, said cylinder having means: whereby communication may be. established between the interior thereof and the interior of said tire, of a piston in said cylinder having a shank extending through said cylinder head, a spring interposed between said ,piston and cylinder head, and a stop member carried by said shank at the exterior of said cylinder head, the spacing of said piston and stop member being such as to cause said spring to be 1neld between said piston and head under an initial comprcssion sullicieut to prevent movement of said piston under pressures below a predetermined amount out tov permit such movement when said amount is exeeeded.

T. ln a tire pressure gage. the combination with a cylinder' having at its outer end a. head and atl its inner end means for attachment to a tire valve ste-m, ol a piston in said cylinder having` av shank extending through said cylinder head, a spring interposed between `said piston and said head, a stop member carried by said shank at the exterior of said head, the relative positions of said piston and stop member with respect to said cylinder head being` such as to hold. said spring under a predetermined initial compression between said piston and head, and a manually operated pin extending axially through said stem and adapted to engage and open the tire valve to admit the pressure in the tire to said cylinder beneath said piston.

In a tire pressure gage, thc combination with a cylinder having at its outer end. a head and provided ai; its inner end with means for attachn'ient to a tire and with means whereby connuunicatioii may be established between the interior thereof and the interior ot said tire, of aJ piston in said cylinder having a shank extending through said head. a spring interposed between said piston and headand a stop member carried by said shank at the exterior of said head, thel relative spacing of said piston and stop member with respect to said cylinder head being such as to hold said spring under a predetermined initial compression between saidpiston and head, and said shank being, provided with graduations cooperating with said head when said piston is moved to measure the amount of movement thereof.

.ln testimony whereof I afiix my signature.

KENNETH F. LEES. 

